Apparatus for crimping of filamentary material

ABSTRACT

Filamentary material is crimped by entraining it with a stream of hot gas and inserting it with the stream to an enclosed space having radial venting ports through which the hot gas escapes. Into the same space, but in counterflow to the hot gas, a stream of cool gas is admitted so that it will initially flow counter to the hot gas and the direction of advancement of the inserted filamentary material, and will subsequently radially vent through the venting ports.

I I U mted States Patent 1191 1111 3,849,844

Bauch et a1. Nov. 26, 1974 4] APPARATUS FOR CRIMPING OF [56] References Cited AMENTARY MATERIAL UNITED STATES PATENTS [75] Inventors: Ernst 'Bauch, Hordesholm; Juergen 3,303,546 2/1967 Van Blerk 28/1.3 Beitz, -Neumuenster both of 3,669,328 6/1972 Castelli 28/13 X Germany 3,729,831 5/1973 Kosaka et al. 28/1.4 x 3,802,039 4/1974 Bauch 28/7214 X [73] Assignee: Neumunstersche Maschinen-und Apparatebau Gesellschaft Primary Examiner-L0uis K. Rimrodt Nuemunster, Germany Attorney, Agent, or FirmMichael S. Striker F'l [22] led Jan 19 1973 ABSTRACT [21] Appl 325012 Filamentary material is crimped by entraining it with a Related US. Application D t stream of hot gas and inserting it with the stream to an [62] Division of Ser. No. 207,826, Dec. 14, 19713411. No. 8119108811 Space havmg radal "emmg ports through 3,802,038 WhlCh the hot gas escapes. Into the same space, but in y counterflow to the hot gas, a stream of cool gas is ad- [30] Foreign Application priority Data mitted so that it will initially flow counter to the hot Dec 16 1970 German 1 2061814 gas andthe direction of advancement of the inserted M y i i i filamentary material, and will subsequently radially ar.9, 1971 Germany 2111163 vent through the venting ports.

[52] US. Cl. 28/ 1.3, 28/ 1.4 13 Claims, 5 Drawing Figures [51.] Int. Cl D02g 1/00, D02g 1/16 [58] Field of Search 28/13, 1.4, 72.11, 72.12, 28/7214 I APPARATUS FOR CRIMPING OF FILAMENTARY MATERIAL CROSS-REFERENCE TO RELATED APPLICATION This application is a division of our copending application, Ser. No. 207,826, filed Dec. 14, 1971, now U.S.

.Pat. 3,802,038 granted Apr. 9, 1974 and entitled Crimping of Filamentary Materials.

BACKGROUND OF THE INVENTION The present invention relates generally to the crimping of filamentary materials, and more particularly to an apparatus for effecting such crimping.

In many instances it is necessary or desirable to be able to crimp or texturize filamentary materials, and in particular synthetic plastic filamentary materials, for

instance those of polyamide, polyester, polyolefin or polyacrylic nitrile. It is already known in the art to use for this purpose so-called stuffing boxes into which the filamentary material is forced by engaging rollers. The crimping process may or may not be supplemented by the supply of heat, but in any case crimping is effected by the force of additional filamentary material which is place the engaging rollers previously used for inserting the filamentary material into the stuffing box with a fluid stream, particularly a stream of gas, which is used to entrain the filamentary material and is then directed into the stuffing box from which it is permitted to escape in lateral or radial direction. When the gas thus escapes, the portion of the filament which has just been inserted by the escaping gas into the stuffing box chamber is deprived of acceleration and the resulting drop in its speed of advancement causes the next-following portion or increment-which still moves at the original speed-to push against it and to thus cause it to form crimps. Of course, the pressure exerted upon the filamentary material by'the streamof fluid, such as gas, is less than the pressure which was previously exerted by engaging rollers provided for this purpose; to compensate for this, it is conventional in the art to use heated gas for the entraining operation, in order to facilitate the crimp formation by plasticizing the synthetic filamentary material.

Apparatus known from the art for carrying out crimping with the aid of a stream of hot gas utilizes a chamber having a medium diameter which is greater than that of the inlet conduit through which the pressurized gas stream and the filamentary material are supplied. The chamber is provided with venting ports -that is in part its circumferential wall is constituted by individual bars-and this permits the stream of heated gas to escape radially. It has been found, however, that in operation of this priorart device difficulties tend to occur. The pressurized stream of gas presses the plug of filamentary material which forms in the chamber as a result of crimping, out of the outlet end of the chamber and, if the pressure of the gas or the resistance of the filament plug during sliding in the chamber to the 2. outlet end thereof should change, the crimping conditions and therefore the characteristic of the crimped filament will similarly change. Furthermore, the

crimped filament is ejected from the chamber'in still hot condition so that it cannot be immediately withdrawn for taking up, because the tensile force acting upon the crimped filament during withdrawing would disadvantageously influence the crimping of the still hot filament. It is therefore necessary in the prior art to use a collecting receptacle, for instance in the form of a bag, a basket or a tubular container into which the crimped yarn can drop out of the outlet end of the chamber, to cool off before it can be withdrawn for winding up.

SUMMARY OF THE INVENTION It is a general object of the present invention to overcome the disadvantages of the prior art.

More particularly, it is an object of the present invention to provide an improved apparatus for crimping filamentary materials which is not posssessed of the disadvantages of the prior art.

One feature of the invention resides, briefly stated, in

' an apparatus for crimping filamentary materials which comprises an enclosed space having axially spaced inlets and outlets and radial venting ports intermediate the same. A filamentary material to be crimped is entrained and inserted with a stream of hot fluid into the inlet so that the material advances towards the outlet and hot gas vents radially through the venting ports. Into the enclosed space, in the region of the outlet, there is further admitted a stream of cool fluid for initial counterflow to the direction of advancement of the filamentary material and for subsequent radial venting through the venting ports.

Of course, the cool fluid could be vented separately from the hot fluid, but it is simpler and therefore more advantageous to vent them jointly. In any case, how ever, the present invention overcomes the disadvantages of the prior art. It is desirable that the crimped filamentary material be so guided out of the enclosed space that it will move in the cool fluid which advances in counterflow to it into the space.

The present invention provides for a significant improvement in the effectiveness of the'c rimping. On the one hand, the counterpressure which builds up at the outlet end of the space as a result of the incoming cool fluid tends to result in a more rapid and more reliable development of a plug of crimped filamentary material in the space when the apparatus is first put into service. Furthermore, the resistance or counterpressure provided in this manner is much more uniform than that j will negate one another as between the hot and the cool fluid, so that the possibility of uneven crimping is further removed.

It will be appreciated that the apparatus according to the present invention can be employed with various types of filamentary materials, for instance multifilaments (endless yarns), mono-filaments, fiber filaments and chopped-fiber ribbons. It is particularly advantageous for synthetic plastic filamentary materials of the earlier mentioned synthetic plastics.

The utilization of cool gas, which preferably is supplied in the temperature range of between substantially 4 and C, with the preferred temperature being substantially 10 C, assures that the filament will be adequately cooled at that end of the filament plug which faces the outlet of the enclosed space or chamber, before it leaves the chamber. This means that the crimp in the filamentary material is much less susceptible to change as a result of the application of tensile forces upon the filamentary material. that is of forces which will necessarily develop when the filamentary material is directly withdrawn from the crimping chamber. Thus, the filamentary material can be directly withdrawn from the crimping chamber by suitable means, for instance engaging rollers or the like, contrary to what is known from the prior art. Moreover, such withdrawal can take place at constant speed, as does the supply of additional filamentary material into the chamber for crimping purposes, so that for all intents and purposes the quantity of filamentary material accommodated in the crimping chamter at any moment of time remains practically constant; this, in turn, further assures an even and uniform crimping effect.

The present invention contemplates the use of heated air for the entraining and inserting of the filamentary material, as the preferred hot fluid. This is in keeping with what is already known from the prior art, but it should be understood that other fluids, for instance a stream of water vapor or steam, can also be employed if, for example, the character of the filamentary material makes this desirable. The temperature of the hot fluid will largely depend upon the type and character of the filamentary material to be crimped, the fineness of the filaments, the operating speed and the length of the apparatus utilized, in particular the length of the guidance tube through which the filamentary material passes prior to entry into the enclosed space or crimping chamber. The invention contemplates for the stream of hot fluid a temperature range of between substantially l80340 C, with the currently preferred temperature being substantially 220 C. The temperature must be so selected within the above range, that as the filamentary material leaves the guidance tube and enters into the crimping chamber it will be at such a temperature as to make it possible for the filament to become readily crimped at low pressure. The particular temperature to be used for a particular filamentary material within the above range can be readily determined by routine experimentation. Particularly if the filamentary material is of relatively heavy gauge or thickness, the use of undesirably high temperature for the stream of hot fluid and excessively long guidance tubes can be avoided if the filamentary material is subjected to preliminary heating, for instance by guiding it over a heated surface, before it becomes entrained.

Experiments have shown that the apparatus according to the present invention can operate at relatively high filament speeds, for instance, filamentary advancement speeds of 500 meters per minute or higher. On the other hand, the present apparatus also permits the use of lower filamentary speeds of, for instance, 100-200 m/min if and when desired. In addition, the thickness or titer of the filamentary material to be crimped may vary within a wide range, for instance, between ISO and 3,600 denier, and multi-filaments can be subjected to crimping both without twisting or with a slight previous twist.

A further improvement in the effects achieved with the present apparatus can be obtainedand in particular a more even crimping can be achieved-if the gas surrounding the crimping chamber, that is, the gas which is in the space contiguous to the crimping chamber, is maintained at a slight underpressure, that is if it is maintained at a pressure between approximately 0.0l0.l atmosphere (preferably 0.02-0.04 atmosphere) lower than the ambient atmospheric pressure. In particular, if the pressure of the gas in this contiguous space can be made continuously adjustable and can be maintained at a constant value, the most advantageous operating conditions for a given circumstance can be selected. This can, for instance, be achieved by providing a pressure measuring device which measures the pressure of the gas in the space contiguous to the chamber and which provides control impulses which in turn control the quantity of air withdrawn from this contiguous space. This means that even if operating conditions vary, the pressure of the gasusually air-in the space contiguous to the crimping chamber and can be maintained at the desired value.

It is further advantageous to accommodate the quantity of hot gas to the degree of crimp which is desired to be obtained, and to maintain the quantity of hot gas constant during operation, for instance by regulating its pressure, and the same considerations, of course, apply to the quantity of cool gas. The temperature of the hot gas should also be regulatable, in particular it should be possible to maintain it constant in order to obtain a uniform crimping effect. If air at room temperature is used as the cool gas, a temperature regulation of the cool gas will usually not be necessary.

An apparatus according to the invention may comprise first means surrounding an enclosed space having axially spaced inlets aNd outlets and radial venting ports intermediate the same. Second means will be provided for entraining and inserting with a stream of hot fluid into the inlet a filamentary material to be crimped, so that such material advances towards the outlet and becomes crimped whereas the hot gas vents radially through the venting ports. Third means is provided for admitting into the space, in the region of the outlet and in counterflow to the direction of advancement of the filamentary material, a cool gas for subsequent radial venting through the venting ports. The filamentary material is supplied to the inlet through a guide tube whose inner diameter is either the same as or slightly smaller than the inner diameter of the enclosed space, that is of the crimping chamber, and the crimped thread is withdrawn from the outlet of the chamber through an additional guide tube which advantageously has a larger diameter than the inner diameter of the chamber. The reason for this is that, contrary to the guide tube through which the filament enters into the chamber, high flow speeds of the cooling gas which flows through this guide tube at the outlet of the chamber is counterflow to the crimped filament being withdrawn are not desired.

The first means surrounding and defining the chamber may be provided in its circumferential wall with longitudinal slots constituting the venting ports. However, the circumferential wall may also be provided by forming it of a plurality of individual lamellae which are mounted in substantially star-shaped configuration in carrier plates located at the opposite axial ends of the chamber. The edges 'of these lamellae, which latter may and between them are formed narrow longitudinal slots or venting ports which, however, increase in crosssection strongly in radially outward direction. Such a chamber can be produced very readily and has a greater structural stability than a chamber which is made of individual rods. At the same time such a chamber can be readily exchanged for another if and when necessary and the venting of both the hot and cool gas is made very simple.

It is advantageous-and if underpressure is to be maintained in the space contiguous to the chamber, it is necessary-to provide the chamber with an outwardly spaced circumferential jacket into which the gases vent. From this jacket they can then be withdrawn, and of course the jacket also serves to reduce the noise of the venting gas. Moreover, withdrawal of the venting gas from this jacket also facilitates inserting of the filamentary material to the chamber.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING I DESCRIPTION OF THE PREFERRED EMBODIMENTS The exemplary embodiment of the apparatus which isillustrated in FIGS. 1-5 utilizes a tubular member 1 in which a crimping chamber 5 is inserted. An inlet nipple 3 for hot gas and an inlet nipple 4 for cold gas are provided at axially spaced locations of the tubular member 1, communicating with the interior of the latter. y

In the illustrated embodiment the crimping chamber 5 (compare FIGS. 2 and 3) is made of a plurality of strip-shaped lamellae 6, of which there are twelve provided in this embodiment and which are secured at their respective opposite ends to ring-shaped carrier members 7 and 8. Of course, a larger or smaller number of such lamellae 6 (for instance 8 or 24) can also be utilized. They are arranged in star-shaped configura tion in this embodiment and define with one another a plurality of axially elongatedslots or venting ports 2 whose cross-section increases substantially in radially outward direction (see FIG. 3).

The inlet end of the chamber 5 communicates with a supply and guidance tube 9 the windened inlet end of which is in turn provided with gas guides 10 for the hot gas and with a filament inserting tube 11 into which the filament F is inserted. If desired a conventional heater, here diagrammatically illustrated as heating means HM, may be provided upstream of the tube 11 so that the filament will be heated before it enters the tube 11. The reasons for-this have been set forth earlier. In FIG. 1 the upper part of the tube l is surrounded by a housing 12 which is filled with a suitable thermally insulating material 13, in order to reduce heat losses as much as possible.

Communicating with the outlet of the chamber 5, which is axially spaced from the inlet, is a withdrawal or outlet tube 114 which is configurated analogously to the tube 9 but has a larger internal diameter than the internal diameter of the chamber 5, by contrast to the tube 9. The tube 14 is also provided with gas guiding channels 15 for the cool gas supplied by the inlet nipple 4, and inserted into the tube 14 downstream of the nipple 4as seen with respect to the direction of advancement of the filament Fthere is provided a conventional thread guidance nozzle 16.

A housing l7, l8 surrounds the chamber 5 and portions of the tube 14 and a suction conduit 19 communicates with this housing. The purpose of the housing is thus not only to reduce the noise of gas escaping through the ports 2, but also to permit withdrawal of the escaping gas from the space contiguous with the chamber 5. r

The filamentary material F is inserted into the chamber 5 by the suction of the hot gas entering through the inlet nipple 3 and flowing under pressure through the tube 9. It is drawn through the tube 11, heated in the tube 9 by the hot gas and inserted into the chamber 5. Because in the chamber 5 the incoming hot gas is immediately vented in radial direction, the just inserted increment of filament loses its propulsion and this, in

. combination with counter-pressure existing at the region of the outlet end of the chamber 5 due to the incoming cool gas, results in retardation of the increment of filament and in crimping due to the still advancing next-following increment which is being carried out of the tube 9 into the chamber by the flowing stream of hot gas. The filament thus becomes crimped in the chamber 5 and is cooled by the counterflowing cool gas as it advances through the tube 14, and before it is withdrawn in crimped state through the nozzle 16.

The supply of hot gas into the nipple 3 takes place via the conduit 33 (see FIG. 4) which communicates with a source in form of a vessel 37. The vessel in this illustrated embodiment receives air via a line 32 and the interior of the vessel is provided with a heater 37a, here electrically operated as illustrated, so that the air is I heated before it enters into the conduit 33.

Interposed in the conduit 33 downstream of the vessel 37 is a valve 24 by means of which the flow of air can be controlled. Downstream of the valve 24 there is provided a pressure indicating instrument 25 and downstream of that a regulating valve 26. The latter is in turn provided with a pressure indicating device 34 and, finally, downstream of the valve 26 there is located a temperature measuring device, here illustrated as a thermometer 27. The thermometer 27 is in turn connected via a suitable conductor 35 with a regulating device 36 which regulates the supply of electrical energy to the heater 37a as a function of the temperature indication derived from the thermometer 27. Thus, the temperature of the heated gas flowing through the line 33 can be maintained constant or nearly so. The necessary gas pressure is selected with the regulating valve 26 and can be supervised via the instrument 34. The instrument 25 indicates the pressure in the line 33 upstream of the valve 26, and this pressure must always be higher than the pressure which is selected with the valve 26.

The cool gas is supplied to the inlet nipple 4 via a conduit or line 44 communicating (see FIG. 5) with a vessel 41. Gas is supplied via a line 40, for instance as air, and interposed between the line 40 and the line 44 is a coiled or otherwise convoluted portion 41a located within the vessel 41. In this portion 41a the air or other gas is cooled by heat exchange, and cooling medium in this instance is water which is supplied via an inlet conduit 42 and removed via an outlet conduit 43 both of which communicate with the vessel 41. A regulating valve 39 is interposed in the water inlet conduit 42 and is electrically controlled, being connected via a conductor 38 with a temperature sensing device, such as a thermometer 31, which is interposed in the line 44. Thus, the supply of cooling water into the vessel 41 is regulated as a function of the gas temperature detected by the thermometer 31 so that the gas temperature is maintained constant or nearly so at all times.

Also located in the line 44 intermediate the vessel 41 and the thermometer 31 is a valve 28 for shutting off the flow of gas, a pressure indicating device 29 and a regulating valve 30 provided with a pressure indicating device 45. The pressure inthe line 44 upstream of the valve 30 is read off the device 29 and must always be higher than the regulative pressure which is set with the valve 30 and which is read off the instrment 45.

The suction conduit 19 communicates, in the diagrammatically illustrated manner (see FIG. 1) with a ventilator 23 of any suitable constructionso that gas can be withdrawn from the space between the jacket l7, 18 on the one hand and the chamber 5 on the other hand, via the conduit 19. Interposed in the conduit 19 intermediate the jacket and the ventilator 23 is a pressure measuring device 21, preferably in form of the illustrated U-shaped tube which is filled with water and provides very precise indication of the very small pressure differences in millimeters of water column, and intermediate it and the ventilator 23 there is provided a regulating valve 22. The pressure fluctuations detected by the device 21 indicate to an operator (or may be used for automatic control of) necessary adjustment of the regulating valve 22 in order to assure that sufficient gas is withdrawn at all times through the suction conduit 19 so as to maintain the pressure in the housing or jacket 18 constant and at a slight underpressure with respect to the atmospheric pressure, within the range mentioned above and for the reasons already outlined.

Because the quantity and temperature of the hot and cold gases supplied to the chamber 5 are maintained constant, and because the gas pressure in the jacket 18 is maintained constant and at sub-atmospheric pressure, the forces acting upon the filamentary material in the chamber 5 are very uniform and a correspondingly uniform crimping of the filamentary material in the chamber 5 is thereby obtained.

The devices 36 and 39 are well known and entirely conventional. By way of example, it is pointed out that such devices are manufactured by the JUMO M.K. Juchheim GmbH & Co., 64 Fulda, Germany, where they are commercially obtainable under the designation JUMO-TROFE-Therm-Regler Type G. The valves 26 and 30 are also well known and are for instance available as regulating valves Types RV8, RVl8 and RV 25 from the Forkardt Company of Germany.

For further clarity of disclosure, the following operating example is provided:

A filament of the type nylon 6 was longitudinally oriented and was composed of 68 mono-filaments having a total titer of 1256 dtex. This filament was preheated to 160 C and supplied to the tube 11 at a speed of 600 m/min.

Hot gas was admitted via nipple 3 at a temperature of 220 C and at a pressure of 4.75 kg/cm Cool gas was admitted via nipple 4 at a temperature of l0 C and via ventilator 23 sufficient gas was withdrawn via suction conduit 19 that an underpressure of mm water column was registered by gauge.

The crimped, filament was withdrawn by the diagrammatically illustrated withdrawing means WM (FIG. 1) via the nozzle 16 at a speed of 340 m/min.

It will be appreciated that with the present invention the disadvantages outlined with respect to the prior art in the introductory portions of the specification, have been overcome and that a method and an apparatus have been provided for crimping of filamentary materials, especially of synthetic plastic filamentary materials, which assure substantially more uniform crimping with less problems than heretofore.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of applications differing from the types described above.

While the invention has been illustrated and described as embodied in an apparatus for crimping of filamentary materials, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for vari ous applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desiged to be protected by Letters Patent is set forth in the appended 1. Apparatus for crimping filamentary materials, comprising first means surrounding an elongated space having axially spaced ends and radial venting ports intermediate the same; second means for entraining, heating and inserting with a stream of hot fluid into said enclosed space in the region of one of said ends and in a first direction a filamentary material to be crimped, so that such material becomes plasticized, advances toward the other of said ends and becomes crimped whereas said hot fluid vents radially through said venting ports; third means for admitting into said enclosed space, in the region of said other end and in a second direction counter to said first direction, a cool gas for cooling said crimped filamentary material and setting the crimp therein and for subsequent radial venting through said venting ports; and fourth means for withdrawing said filamentary material with set crimp from said enclosed space.

2. Apparatus as defined in claim 1, said third means including a tubular outlet member registering with and projecting axially from said space.

3. Apparatus as defined in claim 2; said fourth means comprising an outlet nozzle for said filamentary material located in said tubular member and spaced from said space.

4. Apparatus as defined in claim 2, said second means comprising an inlet opening and a tubular inlet member-located outside said space and projecting away from said inlet opening in axial registry therewith; and wherein said outlet member has a diameter which is greater than the diameter of said inlet member.

5. Apparatus asdefined in claim 1,- said first means comprising a pair of axially spaced support members,

and a plurality of bar members mounted in and extending between said support members in a substantially star-shaped cross-sectional pattern and defining with said support members said space.

6. Apparatus as defined in claim 1; further comprising a casing surrounding said first means with clearance from said venting ports; and withdrawing means com municating with the interior of said casing for withdrawing fluid therefrom.

7. Apparatus as defined in claim 6; said withdrawing means including at least one withdrawing conduit, and

a fluid-pressure measuring device operative for measuring the pressure of fluid withdrawn through said conduit.

8. Apparatus as defined in claim 7; and further comprising a pressure-regulating valve installed in said withdrawing conduit.

9. Apparatus as defined in claim 1, said second means comprising a supply conduit for a stream of hot fluid, and a pressure measuring device for measuring the pressure of hot fluid in said supply conduit.

10. Apparatus as defined in claim 9, said second means further comprising a pressure regulating valve installed in said supply conduit.

11. Apparatus as defined in claim 9, said second means further comprising a temperature measuring device for measuring the temperature of said stream of hot fluid.

12. Apparatus as defined in claim 1, said third means comprising a feed conduit for feeding cool gas into said space, and a pressure measuring device installed in said feed conduit for measuring the pressure of said cool gas therein.

13. Apparatus as defined in claim 12, said third means further comprising a pressure regulating valve installed in said feed conduit. 

1. Apparatus for crimping filamentary materials, comprising first means surrounding an elongated space having axially spaced ends and radial venting ports intermediate the same; second means for entraining, heating and inserting with a stream of hot fluid into said enclosed space in the region of one of said ends and in a first direction a filamentary material to be crimped, so that such material becomes plasticized, advances toward the other of said ends and becomes crimped whereas said hot fluid vents radially through said venting ports; third means for admitting into said enclosed space, in the region of said other end and in a second direction counter to said first direction, a cool gas for cooling said crimped filamentary material and setting the crimp therein and for subsequent radial venting through said venting ports; and fourth means for withdrawing said filamentary material with set crimp from said enclosed space.
 2. Apparatus as defined in claim 1, said third means including a tubular outlet member registering with and projecting axially from said space.
 3. Apparatus as defined in claim 2; said fourth means comprising an outlet nozzle for said filamentary material located in said tubular member and spaced from said space.
 4. Apparatus as defined in claim 2, said second means comprising an inlet opening and a tubular inlet member located outside said space and projecting away from said inlet opening in axial registry therewith; and wherein said outlet member has a diameter which is greater than the diameter of said inlet member.
 5. Apparatus as defined in claim 1, said first means comprising a pair of axially spaced support members, and a plurality of bar members mounted in and extending between said support members in a substantially star-shaped cross-sectional pattern and defining with said support members said space.
 6. Apparatus as defined in claim 1; further comprising a casing surrounding said first means with clearance from said venting ports; and withdrawing means communicating with the interior of said casing for withdrawing fluid therefrom.
 7. Apparatus as defined in claim 6; said withdrawing means including at least one withdrawing conduit, and a fluid-pressure measuring device operative for measuring the pressure of fluid withdrawn through said conduit.
 8. Apparatus as defined in claim 7; and further comprising a pressure-regulating valve installed in said withdrawing conduit.
 9. Apparatus as defined in claim 1, said second means comprising a supply conduit for a stream of hot fluid, and a pressure measuring device for measuring the pressure of hot fluid in said supply conduit.
 10. Apparatus as defined in claim 9, said second means further comprising a pressure regulating valve installed in said supply conduit.
 11. Apparatus as defined in claim 9, said second means further comprising a temperature measuring device for measuring the temperature of said stream of hot fluid.
 12. Apparatus as defined in claim 1, said third means comprising a feed conduit for feeding cool gas into said space, and a pressure measuring device installed in said feed conduit for measuring the pressure of said cool gas therein.
 13. Apparatus as defined in claIm 12, said third means further comprising a pressure regulating valve installed in said feed conduit. 